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Looks like those triple turbo rumors 6 cylinder rumors for the X3 M were true. Auto Express reports they confirmed the triple turbo 3.3 liter with head of M Dr. Nitschke. 450 horsepower is the expected output with 2 turbos fed by gasoline and 1 that is electric. How would this work? We aren't entirely sure how BMW plans to arrange them but the attached diagram may help resolve how the turbos could be positioned with an inline 6 with the electric turbo in the middle working as a sort of quasi-compound turbo setup.

Volumetric or thermal efficiency maybe. MPG doesn't produce more power, usually the opposite as more power needs more fuel.

Big engines can be but smaller engines usually are.

Just forget MPG for a while, as other readers might not be that interested in it

Wärtsilä's latest engine achieves 50% efficiency, i.e. it generates a lot of power (50%) vs heat compared to the typical 30-40% efficiency ratings of car sized engines which are small since they need to fit in a car... So, big engines seem to be more efficient

If BMW would be able to increase the efficiency of a given engine, it means more power! or alternatively lower fuel consumption, in practice it means both as they want to enhance in both fronts.

Exactly! Read my post above, Sticky. The diagram you posted shows a twin turbo system with a third turbo driven by exhaust gases. The press is claiming the &quot;turbo&quot; is driven by electricity, not exhaust. It's not a turbo in that case.

Exactly! Read my post above, Sticky. The diagram you posted shows a twin turbo system with a third turbo driven by exhaust gases. The press is claiming the &quot;turbo&quot; is driven by electricity, not exhaust. It's not a turbo in that case.

Just speculation, but it could be a turbo that uses a motor to spool up at near idle RPM - giving the sensation of instant boost. It still could be considered a turbo (with an electric motor) yet still use the exhaust gas after an initial "small spool"?

Also - this 3rd turbo could help drive the other two turbos since the car will instantly start to create more torque/power - it would then also be creating more exhaust - helping drive the other two turbos...

Just a thought. Awesome if it works AND they can spin the engine to 8k.

Just speculation, but it could be a turbo that uses a motor to spool up at near idle RPM - giving the sensation of instant boost. It still could be considered a turbo (with an electric motor) yet still use the exhaust gas after an initial "small spool"?

Also - this 3rd turbo could help drive the other two turbos since the car will instantly start to create more torque/power - it would then also be creating more exhaust - helping drive the other two turbos...

Just a thought. Awesome if it works AND they can spin the engine to 8k.

Funny thing, I was thinking about the possibility of an electric hybrid turbo right after I made the post. In any case, I assume the "electric turbo" could be used for instant low rpm boost, and could be bypassed at high rpm. This would allow the main turbos to be larger for greater high rpm boost without sacrificing low rpm spool up.

how come it looks like the compressed are from the first 2 turbos are blowing into the third to turn that compressor, then i guess it would continue into the IC, so i dont see how thats electric,also wouldnt you have some paracitic loss by having to use your compressed air(free power) to then turn this other turbine??

We don't know, it could, it could also be 100% electric. Either way, no reason an impeller can't be spooled electrically without any mechanical connection to the motor (like with belts) as a super charger would require essentially being an electric turbo.

Exactly! Read my post above, Sticky. The diagram you posted shows a twin turbo system with a third turbo driven by exhaust gases. The press is claiming the &quot;turbo&quot; is driven by electricity, not exhaust. It's not a turbo in that case.

how come it looks like the compressed are from the first 2 turbos are blowing into the third to turn that compressor, then i guess it would continue into the IC, so i dont see how thats electric,also wouldnt you have some paracitic loss by having to use your compressed air(free power) to then turn this other turbine??

That is just a diagram of what it could look like, it has nothing to do with BMW's own design.